Brilliant and witty as a piece of staging, blistering as an ensemble performance, Ligeti's Le Grand Macabre opened at English National Opera on Thursday after enough advance cloaca-and-dagger leakage to very nearly spoil the fun.

There's little we didn't know about the protrusions and pertusions of the busty fibreglass colossus which dominates the stage, in and out of whose semi-detached limbs and obliging orifices the action takes place. With bodily evacuation turned into an art form – at one point the vast exposed bowels became a resonant grotto of unearthly delights – this was a veritable succès d'intestine.

ENO gave the UK production of this work, in its original 1970s form, 27 years ago. This new co-production, already acclaimed in Brussels and Rome, uses Ligeti's 1996 revision, another UK first. The great coup was to ensnare the Catalan "total theatre" company La Fura dels Baus to stage the work, which they did with a comedic flair which could not entirely disguise the occasional longueurs but came close. A single set usually spells monotony but the variations achieved through poetic video projections and cunning use of the revolve made this show endlessly absorbing.

The perennial difficulty with absurdist drama is that you rarely care about plot or characters. Broadly, we are in a no-time, no-place land whose imagery owes much to the paintings of Brueghel. Once you've established there's a Chief of the Secret Police, a court astrologer, a Venus and a Prince Go-Go, you know the score: high-pitched sex and death, much running around and screeching and some good old S'n'M with the carpet beater.

No advance publicity, however, conveyed the glorious invention of the music, which glides and cascades as one original idea elides seamlessly with another. The Hungarian Ligeti, who died three years ago, ranks as one of the leading modernists of the 20th century, a contemporary of Boulez and Stockhausen with whom he both shared and battled, always more sentient and flexible in his musical ideas. But he was also, in a sense, a pioneering post-modernist, borrowing from Monteverdi, Rossini, Wagner and others, as well as ragtime, in this, his only opera.

The luscious love music for Amanda and Amando (Rebecca Bottone and Frances Bourne), the yelping coloratura for Gepopo the police chief (Susanna Andersson) and the final, mysterious passacaglia, whispered and delicate, were just some of the high points, together with spangly outbursts of tuned percussion and rude volleys of brass. Susan Bickley, Andrew Watts, Wolfgang Ablinger-Sperrhacke and Pavo Hunka gave brave, bold performances. Baldur Brönnimann conducted with committed dexterity and the orchestra shone.

In Verdi the sex may look safer but the music is equally radical and scorching in impact. David McVicar's staging of La traviata, first seen at Scottish Opera last October, has opened at the Wales Millennium Centre in the first leg of Welsh National Opera's autumn tour. Not all was well on the first night, with some clumsy scene changes which interrupted McVicar's carefully conceived dramatic flow. But this is a thoughtful, astute take on Verdi's middle-period masterpiece.

Tanya McCallin's beautifully observed monochrome designs, lit by Jennifer Tipton, update the work by a decade or so to the age of bustles and Tissot. Alfie Boe offers a light voiced, sympathetic Alfredo. Dario Solari's dignified Germont was smoky-toned and lyrical. As Violetta, Greek soprano Myrto Papatanasiu looked properly slim and, as it were, consumptive but seemed vocally inhibited, perhaps from first night nerves. The conductor Andrea Licata led a secure account, with expert contributions from the WNO orchestra and chorus. The performance hasn't yet got fire in its belly but surely will as the run proceeds.

La traviata creates its own world out of a private drama. Don Carlo, or Don Carlos in the original French version, gathers an entire political landscape into its embrace, at the heart of which is a love triangle of the utmost intimacy. This reworking of Schiller ranks as one of Verdi's finest operatic achievements though some groan at its length and scale, and at the uncertainty of two of its central characters, the jejune Carlo himself and his compromised blood-brother, Rodrigo, sung with febrile intelligence by Simon Keenlyside.

But in this exciting first revival of Nicholas Hytner's 2008 production, dramaturgical snags receded. Designed by Bob Crowley and lit by Mark Henderson, it looks magnificent, with its ingenious flourish of Spanish baroque sobriety and gaudy, gilded splendour. Chorus and orchestra responded vividly to Semyon Bychkov's sweeping, expansive tempi. The cast was exceptional, led by Jonas Kaufmann in the title role. This remarkable Munich-born tenor, seemingly faultless in every musical decision he makes, has just released a solo disc of German repertoire. Yet his handling of Italian opera shows his versatility, with none of the usual puffed-up tenor show-off tendencies.

The Italian bass Ferruccio Furlanetto returns as a spellbinding, agonised Philip II. Reprising the role of Elisabetta, Russian soprano Marina Poplavskaya compensates for bumpiness mid-range with a mesmerising performance of queenly hauteur and inner torment. She looks like a movie star, which helps. John Tomlinson, himself a bit of a matinee idol grise, had been kohl-ed up like a sunken-cheeked el Greco prelate, grotesque in authority as the Inquisitor. Verdi may inhabit an older operatic tradition of precisely the kind Ligeti wanted to challenge. Yet here he shows us the grand macabre, bodied forth on an all too human scale.